arraystack.java

基本数据结构

package stack;

public class ArrayStack implements Stack
{
	private int top=-1;
	private Object[] stack;
	public class FullStackException extends RuntimeException{

		/**
		 * 
		 */
		private static final long serialVersionUID = -907728676469025250L;}
	public ArrayStack(int maxElements){stack=new Object[maxElements];}
	public boolean isEmpty(){return top==-1;}
	public Object peek()
	{
		if (top<0)throw new java.util.EmptyStackException();
		return stack[top];
	}
	public void push(Object o)
	{
		if (top==stack.length-1)throw new FullStackException();
		stack[++top]=o;
	}
	public Object pop()
	{
		if (top<0)throw new java.util.EmptyStackException();
		return stack[top--];
	}
	public Object getNext()
	{
		if(isEmpty())throw new java.util.EmptyStackException();
		else return stack[top--];
	}
	public int getLength()
	{
		return top;
	}
}